Dynamic diffraction of planar X-rays in a crystal lattice with a weak deformation field

Abstract

In this paper, we consider the problem of the formation of a wave field during dynamic X-ray diffraction under conditions of weak deformation of the crystal lattice induced by a temperature gradient directed along the diffraction vector. Within the framework of the Takagi equations, which describe the propagation of the amplitudes of transmitted and reflected waves in the grating, analytical solutions dependence on the deformation parameters of these amplitudes are given. The angular width of the reflected X-ray radiation, as well as its dependence on the thickness of the single crystal, has been studied. It is shown that with increasing deformation, the rocking curves of the crystal slowly broaden, and their maximum intensity increases, reaching unity (the case of complete transfer). With a further increase in the deformation of the reflecting planes, the rocking curves continues to widen, and their maximum slowly decreases. It is also shown that the angular width of the complete transfer x-rays is directly proportional to the thickness of the sample under study. All observed phenomena are given a theoretical interpretation based on the general theory of dynamic scattering based on the Takagi equations and the eikonal approximation for weakly deformed crystal lattice fields.